Tapping sleeves are conventionally used to connect a branch pipe to a main pipe in a fluid supply system such as a waterworks, without shutting down the main pipe. This procedure is usually referred to as making a pressure tap because the fluid pressure is maintained in the main pipe while a connection is made to a branch pipe. The connection is made by cutting a hole in the pressurized main pipe using a power or manual tapping machine. The tapping machine extends into a branch outlet pipe on the tapping sleeve through a gate valve which is closed after a cutaway portion of the main pipe is removed by the tapping machine through the branch outlet pipe and the gate valve. The gate valve remains to control fluid flow from the main pipe through the later installed distribution piping supplied by the branch outlet pipe.
A specialized type of gate valve is presently used in making a pressure tap. This specialized tapping gate valve is equipped with a bolted flange having either a raised face or recessed face on its branch outlet pipe side and a mechanical joint on its tapping machine receiving side. The raised face or recessed face flange of the gate valve is bolted to a raised face or recessed face flange provided on the outlet end of the branch outlet pipe of the tapping sleeve. The raised or recessed faces are provided to insure vertical alignment of the gate valve with the outlet pipe of the tapping sleeves. A bolted flange joint has been considered necessary for use with a tapping sleeve so that the tapping cutter accurately cuts the opening in the main pipe and also withstands the large torque and axial thrust applied to the connection by the tapping machine.
The use of a bolted flange on the branch outlet pipe requires contractors to obtain and inventory specialized tapping gate valves which are equipped with a bolted raised face or recessed face flange on one side and a mechanical joint on the other side of the gate valve. Additionally, the time required to make a pressure tap using these specialized tapping gate valves is substantial because of the difficulty in connecting bolted flanges compared to the time required to complete mechanical joint connections.
Accordingly, it is an object of this invention to provide a tapping sleeve assembly for making a pressure tap which can be welded to the tapping sleeve outlet pipe and connected directly to a mechanical joint gate valve thereby eliminating the need for use of a specialized raised face or recessed face tapping valve.
Another object of this invention is a mechanical joint branch outlet pipe that is adaptable to both "bolt on" and "weld on" tapping sleeves or partial tapping sleeves.
Still another object of this invention is a tapping sleeve which may be used with conventional cast iron, steel or plastic pipe.
Yet another object of this invention is a tapping branch pipe sleeve having an integral mechanical joint adaptor.
A further object of this invention is a tapping sleeve branch pipe having an integral mechanical joint adaptor and an integral semi-circular tapping sleeve portion.
In its broadest aspect, this invention provides a pressure tap connection that incorporates all the advantages of a mechanical joint while not limiting the use of modified joint accessories.
Other objects of this invention will be found in the following specification, claims and drawings.